Backrest



FIG. 1 is a perspective view from the front and left side of a backrest according to our design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational view thereof; and,

FIG. 6 is a top plan view thereof.

Throughout the Figures, broken lines showing structure are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a backrest, as shown and described. 